Current diagnostic clinical examinations for cardiomyopathies: a nationwide survey of cardiologists in Japan

Idiopathic cardiomyopathies—including dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), and arrhythmogenic right ventricular cardiomyopathy (ARVC)—are diagnosed after excluding secondary cardiomyopathies caused by systemic diseases or specific etiologies. Although current guidelines recommend several diagnostic examinations to aid in this differentiation, the extent to which these tests are used in routine clinical practice and their associated factors remain unclear. We conducted a nationwide web-based questionnaire survey among physicians of the Japanese Circulation Society. An invitation was sent by email to 25,258 physicians, and responses were collected anonymously between January 10 and February 28, 2024. The questionnaire assessed respondents’ characteristics and whether they would perform diagnostic examinations for each cardiomyopathy using a five-point Likert scale. Responses were categorized into two groups (“always/frequently” vs. “sometimes/rarely/never”), and multivariable nominal logistic regression analysis was performed to examine associations between respondent characteristics and reported routine use of diagnostic tests. Adjusted trends were also assessed for clinical experience and hospital bed categories. Among 1103 (4.4%) respondents, the frequency of diagnostic examinations varied by cardiomyopathy type. A high proportion of respondents (95%) reported that they would perform coronary evaluations in DCM, whereas this proportion was approximately 80% for other idiopathic cardiomyopathies. In contrast, the proportion of respondents reporting frequent use of examinations relevant to the differential diagnosis of secondary cardiomyopathies, such as endomyocardial biopsy (EMB), cardiac magnetic resonance imaging (MRI), and nuclear imaging, was generally low. Multivariable analysis showed that institutional and physician-related factors were associated with reported testing patterns. Respondents working at larger hospitals more frequently reported routine use of most examinations, and those with fewer years of clinical experience more often reported that they would perform MRI in DCM and EMB and MRI in HCM. In addition, respondents reporting less frequent EMB use in DCM also reported less frequent use of MRI and 67 Ga scintigraphy/ 18 F-fluorodeoxyglucose positron emission tomography. In Japan, the proportion of physicians reporting that they would routinely perform several examinations relevant to the differential diagnosis of secondary cardiomyopathies was low, and these responses were associated with physician and institutional characteristics.